I find loading 120 on to plastic reels a lot easier than 35mm. I don't unravel the whole film, but unwind until I find the film leader stuck to the backing paper. I tear the film off, leaving part of the tape stuck to the film, this gives it a stiffer leading edge. I hold the reel in my right hand, with my finger and thumb over the entry slots, and push the film in with my left (holding it at the edges). Once the ball-bearings are met, I hold the film and reel with my left, and pull the leader through the balls. Then it's just a question of cranking the spiral & unwinding the film from the paper in sections.